Most engineering marketing talks about greenfield projects. New processing plants, new mine sites, and blank-sheet design work where the only constraint is the geology and budget. It is the more glamorous end of the industry, but it is not where most Australian mineral processing money is actually spent.
The reality on the ground is brownfield. It is a 1980s comminution circuit that needs a new crusher tied into equipment nobody has complete documentation for anymore. It is a smelter off-gas system that has to be upgraded without stopping production. It is a tailings pipeline that was designed for one ore body and must now handle a different slurry chemistry entirely. These projects do not get conference keynotes, but they are where the real engineering difficulty lies because every decision must account for what is already there.
GPA Engineering, an Adelaide-founded multidisciplinary engineering and an engineering, procurement, and construction management (EPCM) firm operating since 1987, has built a large part of its mining and minerals practice specifically around this kind of work.
Thirty years in the metallurgy, not just the infrastructure
Many engineering consultancies serving mining clients approach projects from the infrastructure side, handling civil works, power distribution, or bulk materials handling without going deeply into the processing chemistry itself.
GPA’s mining and minerals team also works from the other direction. Its stated specialisation covers comminution, including crushing and grinding; beneficiation and separation, including magnetic separation, gravity separation, flotation, dewatering and thickening; hydrometallurgy, including leaching, solvent extraction, ion exchange, electrowinning; and pyrometallurgy, including smelting, refining, offgas handling, acid plants.
That is a genuinely different scope from that of a firm that only undertakes structural and electrical design around a process plant. It means the same team advising on a bulk materials handling upgrade can also work through the metallurgical implications of a leach circuit change and understand how tailings management, water treatment, and energy systems interact with the process itself rather than merely sitting alongside it.
GPA’s project history supports this. Two decades of high-voltage services work at the Port Pirie lead smelter, operated by Trafigura-owned Nyrstar, including a full process control system upgrade, sits alongside water pre-treatment redesign at the Ranger Uranium Mine and evaporation pond design for Olympic Dam’s tailings retention system. These are not small jobs, nor are they not the kind of work typically undertaken by a generalist civil contractor.
The small-to-medium brownfield niche
GPA explicitly focuses on delivering cost-effective solutions across a high volume of small-to-medium-sized projects at brownfield sites, covering commodities including iron ore, copper, zinc, lead, silver, gold and uranium. This is a deliberate positioning choice, and it matters for operators that do not need a mega-project EPC contractor for a chiller upgrade or substation expansion.
The Cadia Chillers Upgrade Project for Newcrest Mining and the 132kV substation upgrade at OZ Minerals’ Prominent Hill operation are good examples of the scale at which GPA typically operates. Newmont (ASX:NEM) acquired Newcrest in November 2023, BHP Group (ASX:BHP) acquired OZ Minerals in April the same year.
Neither project is a headline greenfield development, but both represent the kind of asset integrity and capacity work that keeps an operating mine running reliably between major capital cycles. GPA’s service list — spanning outage planning, integrity management, equipment inspection and assessment, and capital planning — reflects a business designed to support this ongoing maintenance and upgrade cycle rather than one-off construction.
Full lifecycle, not just design
GPA positions itself as covering the entire project lifecycle: concept and Scoping Study, Prefeasibility and Definitive Studies, detailed engineering design, procurement and tender management, construction management, and commissioning, and operations support. EPC, EPCM, and full turnkey delivery models are available depending on the client’s needs.
For a brownfield project, that continuity matters more than it might on a greenfield build. The engineer who scoped the tie-in constraints is better placed to manage the constructability review and commissioning than a team picking up the project cold at each stage gate.
The firm also says it offers owner’s engineer and superintendent services, which is relevant for operators seeking independent technical oversight of a contractor-delivered project rather than handing over full control.
Energy transition inside an existing operation
One area where GPA’s brownfield focus becomes particularly relevant is decarbonisation. Retrofitting renewable energy and hybrid microgrid systems into an operating mine site is a fundamentally different engineering challenge from specifying them for a new development.
GPA’s energy advisory work includes integrating renewables into existing operations, implementing energy management systems to monitor and optimise energy use, and developing hydrogen and biofuel projects, including fuel-cell-powered heavy vehicles for mine sites.
Australian mining companies face increasing pressure from investors, regulators, and communities to reduce emissions at operations designed decades before decarbonisation became an engineering consideration. As a result, this kind of retrofit-focused energy expertise is becoming as commercially relevant as core metallurgical engineering.
With offices across Adelaide, Perth, Brisbane, Darwin, Melbourne and Sydney, and a client list that includes OZ Minerals, Newcrest, and Nyrstar, GPA Engineering has built its mining and minerals practice around a part of the industry that rarely attracts attention but never stops generating engineering work: keeping existing operations running, compliant, and up to date.
Image Credit: gpaeng.com.au/
